With rapid development of information technologies, a manner of storing data using devices is widely applied. However, a storage area of a device is exposed to damage risks, which causes losses of stored data and brings inconvenience and even unrecoverable losses to people. Requirements for data reliability vary in different fields, and for application scenarios in which data reliability is not strictly required, residual data in a storage area is also valuable. Therefore, it is an issue for people to consider how to reduce data loss in a case of a damaged storage area for effective data access.
In the prior art, a redundant array of independent disks (RAID) technology is used for data access, where multiple disks form a disk group, each disk is divided into multiple stripes, and data is segmented into multiple data blocks that are separately stored in different stripes of the multiple disks, where each stripe stores one data block. RAID5 is used as an example. RAID5 includes a disk group and the disk group includes n+1 disks, where n disks are used to store data for access and one disk is used to store redundancy data. When one disk in the disk group becomes faulty, unknown data in the faulty disk may be obtained by calculation using data on the other disks in the disk group, and then all the data can be accessed. When more than one disk in the disk group becomes faulty, unknown data in the faulty disks cannot be obtained by calculation using data on the other disks in the disk group. The disk group goes into a failed state, and data in the disk group cannot be accessed. In this case, a built-in RAID method or a third-party service may be used to access residual data in the disk group, where the residual data is the data on the other disks except the faulty disks in the disk group.
In a process of implementing the present disclosure, the inventor finds that the prior art has at least the following disadvantages.
When more than one disk becomes faulty, without another measure taken, all data in the disk group will be lost, and the data cannot be effectively accessed. In addition, even though a RAID built-in service manner or a third-party service manner is used to access data, the lack of real-time performance of a RAID service or a third-party service makes it impossible to read data conveniently and quickly, and also causes long-time interruption of a service. Moreover, when a third party is involved, data confidentiality cannot be ensured.